From 29a41f0d86b82c2731cc2ab8c8a26272e773e4c3 Mon Sep 17 00:00:00 2001 From: csmoe Date: Mon, 11 May 2020 14:24:57 +0800 Subject: [PATCH 1/5] add ui test for issue-69276 --- src/librustc_typeck/check/mod.rs | 6 +++++- src/test/ui/async-await/issue-69276.rs | 12 ++++++++++++ src/test/ui/async-await/issue-69276.stderr | 8 ++++++++ 3 files changed, 25 insertions(+), 1 deletion(-) create mode 100644 src/test/ui/async-await/issue-69276.rs create mode 100644 src/test/ui/async-await/issue-69276.stderr diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 956e09ec52b..57fdb03250e 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -1659,6 +1659,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId, let prohibit_opaque = match item.kind { ItemKind::OpaqueTy(hir::OpaqueTy { + bounds, origin: hir::OpaqueTyOrigin::AsyncFn | hir::OpaqueTyOrigin::FnReturn, .. }) => { @@ -1671,6 +1672,9 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId, }; debug!("check_opaque_for_inheriting_lifetimes: visitor={:?}", visitor); + for bound in bounds { + debug!("check_opaque_for_inheriting_lifetimes: {:?}", bound.trait_ref()); + } tcx.predicates_of(def_id) .predicates .iter() @@ -1695,7 +1699,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId, "`{}` return type cannot contain a projection or `Self` that references lifetimes from \ a parent scope", if is_async { "async fn" } else { "impl Trait" }, - ), + ) ); } } diff --git a/src/test/ui/async-await/issue-69276.rs b/src/test/ui/async-await/issue-69276.rs new file mode 100644 index 00000000000..224b76e2d90 --- /dev/null +++ b/src/test/ui/async-await/issue-69276.rs @@ -0,0 +1,12 @@ +// edition:2018 + +struct S<'a>(&'a i32); + +impl<'a> S<'a> { + async fn new(i: &'a i32) -> Self { + //~^ ERROR `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope + S(&22) + } +} + +fn main() {} diff --git a/src/test/ui/async-await/issue-69276.stderr b/src/test/ui/async-await/issue-69276.stderr new file mode 100644 index 00000000000..1ebfdfa8b54 --- /dev/null +++ b/src/test/ui/async-await/issue-69276.stderr @@ -0,0 +1,8 @@ +error: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope + --> $DIR/issue-69276.rs:6:33 + | +LL | async fn new(i: &'a i32) -> Self { + | ^^^^ + +error: aborting due to previous error + From 008d90a66a30bc8ff498f8ad47dea315c1853a75 Mon Sep 17 00:00:00 2001 From: csmoe Date: Sat, 16 May 2020 16:01:59 +0800 Subject: [PATCH 2/5] create error code E0754 --- src/librustc_error_codes/error_codes.rs | 1 + src/librustc_error_codes/error_codes/E0754.md | 29 +++++++++++++++++++ 2 files changed, 30 insertions(+) create mode 100644 src/librustc_error_codes/error_codes/E0754.md diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs index e01412bc21c..52d40fd0f2f 100644 --- a/src/librustc_error_codes/error_codes.rs +++ b/src/librustc_error_codes/error_codes.rs @@ -435,6 +435,7 @@ E0750: include_str!("./error_codes/E0750.md"), E0751: include_str!("./error_codes/E0751.md"), E0752: include_str!("./error_codes/E0752.md"), E0753: include_str!("./error_codes/E0753.md"), +E0754: include_str!("./error_codes/E0754.md"), ; // E0006, // merged with E0005 // E0008, // cannot bind by-move into a pattern guard diff --git a/src/librustc_error_codes/error_codes/E0754.md b/src/librustc_error_codes/error_codes/E0754.md new file mode 100644 index 00000000000..e7cea982010 --- /dev/null +++ b/src/librustc_error_codes/error_codes/E0754.md @@ -0,0 +1,29 @@ +`async fn`/`impl trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope. + +Erroneous code example: + +```compile_fail,E0754,edition2018 +struct S<'a>(&'a i32); + +impl<'a> S<'a> { + async fn new(i: &'a i32) -> Self { + S(&22) + } +} +``` + +To fix this error we need to spell out `Self` to `S<'a>`: + +```edition2018 +struct S<'a>(&'a i32); + +impl<'a> S<'a> { + async fn new(i: &'a i32) -> S<'a> { + S(&22) + } +} +``` + +This will be allowed at some point in the future, but the implementation is not yet complete. See the [issue-61949] for this limitation. + +[issue-61949]: https://github.com/rust-lang/rust/issues/61949 From 633e4aafe65cd424cf6c8076869df1b49a4e0ec4 Mon Sep 17 00:00:00 2001 From: csmoe Date: Sat, 16 May 2020 16:08:56 +0800 Subject: [PATCH 3/5] suggest on Self return type --- src/librustc_typeck/check/mod.rs | 67 +++++++++++++++++--------- src/test/ui/async-await/issue-69276.rs | 12 ----- 2 files changed, 43 insertions(+), 36 deletions(-) delete mode 100644 src/test/ui/async-await/issue-69276.rs diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 57fdb03250e..0906c25baef 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -1639,51 +1639,56 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId, struct ProhibitOpaqueVisitor<'tcx> { opaque_identity_ty: Ty<'tcx>, generics: &'tcx ty::Generics, + ty: Option>, }; impl<'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueVisitor<'tcx> { fn visit_ty(&mut self, t: Ty<'tcx>) -> bool { debug!("check_opaque_for_inheriting_lifetimes: (visit_ty) t={:?}", t); + self.ty = Some(t); if t == self.opaque_identity_ty { false } else { t.super_visit_with(self) } } fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool { debug!("check_opaque_for_inheriting_lifetimes: (visit_region) r={:?}", r); if let RegionKind::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = r { - return *index < self.generics.parent_count as u32; + let found_lifetime = *index < self.generics.parent_count as u32; + if !found_lifetime { + self.ty = None; + } + return found_lifetime; } r.super_visit_with(self) } } + let mut visitor = ProhibitOpaqueVisitor { + opaque_identity_ty: tcx.mk_opaque( + def_id.to_def_id(), + InternalSubsts::identity_for_item(tcx, def_id.to_def_id()), + ), + generics: tcx.generics_of(def_id), + ty: None, + }; + debug!("check_opaque_for_inheriting_lifetimes: visitor={:?}", visitor); + let prohibit_opaque = match item.kind { ItemKind::OpaqueTy(hir::OpaqueTy { - bounds, origin: hir::OpaqueTyOrigin::AsyncFn | hir::OpaqueTyOrigin::FnReturn, .. - }) => { - let mut visitor = ProhibitOpaqueVisitor { - opaque_identity_ty: tcx.mk_opaque( - def_id.to_def_id(), - InternalSubsts::identity_for_item(tcx, def_id.to_def_id()), - ), - generics: tcx.generics_of(def_id), - }; - debug!("check_opaque_for_inheriting_lifetimes: visitor={:?}", visitor); - - for bound in bounds { - debug!("check_opaque_for_inheriting_lifetimes: {:?}", bound.trait_ref()); - } - tcx.predicates_of(def_id) - .predicates - .iter() - .any(|(predicate, _)| predicate.visit_with(&mut visitor)) - } + }) => tcx + .predicates_of(def_id) + .predicates + .iter() + .any(|(predicate, _)| predicate.visit_with(&mut visitor)), _ => false, }; + debug!( + "check_opaque_for_inheriting_lifetimes: prohibit_opaque={:?}, visitor={:?}", + prohibit_opaque, visitor + ); - debug!("check_opaque_for_inheriting_lifetimes: prohibit_opaque={:?}", prohibit_opaque); if prohibit_opaque { let is_async = match item.kind { ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => match origin { @@ -1693,14 +1698,28 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId, _ => unreachable!(), }; - tcx.sess.span_err( + let mut err = struct_span_err!( + tcx.sess, span, - &format!( + E0754, "`{}` return type cannot contain a projection or `Self` that references lifetimes from \ a parent scope", if is_async { "async fn" } else { "impl Trait" }, - ) ); + + if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(span) { + if snippet == "Self" { + if let Some(ty) = visitor.ty { + err.span_suggestion( + span, + "consider spelling out the type instead", + format!("{:?}", ty), + Applicability::MaybeIncorrect, + ); + } + } + } + err.emit(); } } diff --git a/src/test/ui/async-await/issue-69276.rs b/src/test/ui/async-await/issue-69276.rs deleted file mode 100644 index 224b76e2d90..00000000000 --- a/src/test/ui/async-await/issue-69276.rs +++ /dev/null @@ -1,12 +0,0 @@ -// edition:2018 - -struct S<'a>(&'a i32); - -impl<'a> S<'a> { - async fn new(i: &'a i32) -> Self { - //~^ ERROR `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope - S(&22) - } -} - -fn main() {} From 8841ede3648b5f12284dae850ec065374fd3af46 Mon Sep 17 00:00:00 2001 From: csmoe Date: Sat, 16 May 2020 17:10:08 +0800 Subject: [PATCH 4/5] bless suggestion on spell out --- src/librustc_error_codes/error_codes.rs | 2 +- .../error_codes/{E0754.md => E0755.md} | 7 +++++-- src/librustc_typeck/check/mod.rs | 2 +- .../ui/async-await/issue-61949-self-return-type.stderr | 5 +++-- src/test/ui/async-await/issue-69276.stderr | 8 -------- src/test/ui/impl-trait/bound-normalization-fail.stderr | 5 +++-- 6 files changed, 13 insertions(+), 16 deletions(-) rename src/librustc_error_codes/error_codes/{E0754.md => E0755.md} (70%) delete mode 100644 src/test/ui/async-await/issue-69276.stderr diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs index 52d40fd0f2f..6467561e509 100644 --- a/src/librustc_error_codes/error_codes.rs +++ b/src/librustc_error_codes/error_codes.rs @@ -435,7 +435,7 @@ E0750: include_str!("./error_codes/E0750.md"), E0751: include_str!("./error_codes/E0751.md"), E0752: include_str!("./error_codes/E0752.md"), E0753: include_str!("./error_codes/E0753.md"), -E0754: include_str!("./error_codes/E0754.md"), +E0755: include_str!("./error_codes/E0755.md"), ; // E0006, // merged with E0005 // E0008, // cannot bind by-move into a pattern guard diff --git a/src/librustc_error_codes/error_codes/E0754.md b/src/librustc_error_codes/error_codes/E0755.md similarity index 70% rename from src/librustc_error_codes/error_codes/E0754.md rename to src/librustc_error_codes/error_codes/E0755.md index e7cea982010..b6eb2e34ccf 100644 --- a/src/librustc_error_codes/error_codes/E0754.md +++ b/src/librustc_error_codes/error_codes/E0755.md @@ -1,4 +1,5 @@ -`async fn`/`impl trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope. +`async fn`/`impl trait` return type cannot contain a projection +or `Self` that references lifetimes from a parent scope. Erroneous code example: @@ -24,6 +25,8 @@ impl<'a> S<'a> { } ``` -This will be allowed at some point in the future, but the implementation is not yet complete. See the [issue-61949] for this limitation. +This will be allowed at some point in the future, +but the implementation is not yet complete. +See the [issue-61949] for this limitation. [issue-61949]: https://github.com/rust-lang/rust/issues/61949 diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 0906c25baef..bd8f628957d 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -1701,7 +1701,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId, let mut err = struct_span_err!( tcx.sess, span, - E0754, + E0755, "`{}` return type cannot contain a projection or `Self` that references lifetimes from \ a parent scope", if is_async { "async fn" } else { "impl Trait" }, diff --git a/src/test/ui/async-await/issue-61949-self-return-type.stderr b/src/test/ui/async-await/issue-61949-self-return-type.stderr index 12fb77d8dd6..fe05754c83f 100644 --- a/src/test/ui/async-await/issue-61949-self-return-type.stderr +++ b/src/test/ui/async-await/issue-61949-self-return-type.stderr @@ -1,8 +1,9 @@ -error: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope +error[E0755]: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope --> $DIR/issue-61949-self-return-type.rs:11:40 | LL | pub async fn new(_bar: &'a i32) -> Self { - | ^^^^ + | ^^^^ help: consider spelling out the type instead: `Foo<'a>` error: aborting due to previous error +For more information about this error, try `rustc --explain E0754`. diff --git a/src/test/ui/async-await/issue-69276.stderr b/src/test/ui/async-await/issue-69276.stderr deleted file mode 100644 index 1ebfdfa8b54..00000000000 --- a/src/test/ui/async-await/issue-69276.stderr +++ /dev/null @@ -1,8 +0,0 @@ -error: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope - --> $DIR/issue-69276.rs:6:33 - | -LL | async fn new(i: &'a i32) -> Self { - | ^^^^ - -error: aborting due to previous error - diff --git a/src/test/ui/impl-trait/bound-normalization-fail.stderr b/src/test/ui/impl-trait/bound-normalization-fail.stderr index f5092044627..04b398f5b52 100644 --- a/src/test/ui/impl-trait/bound-normalization-fail.stderr +++ b/src/test/ui/impl-trait/bound-normalization-fail.stderr @@ -20,7 +20,7 @@ help: consider constraining the associated type `::Assoc LL | fn foo_fail>() -> impl FooLike { | ^^^^^^^^^^^^ -error: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope +error[E0755]: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope --> $DIR/bound-normalization-fail.rs:43:41 | LL | fn foo2_fail<'a, T: Trait<'a>>() -> impl FooLike { @@ -42,4 +42,5 @@ LL | fn foo2_fail<'a, T: Trait<'a, Assoc = ()>>() -> impl FooLike Date: Fri, 22 May 2020 12:14:53 +0800 Subject: [PATCH 5/5] resolve error code e0760 --- src/librustc_error_codes/error_codes.rs | 2 +- src/librustc_error_codes/error_codes/{E0755.md => E0760.md} | 2 +- src/librustc_typeck/check/mod.rs | 2 +- src/test/ui/async-await/issue-61949-self-return-type.stderr | 4 ++-- src/test/ui/impl-trait/bound-normalization-fail.stderr | 4 ++-- 5 files changed, 7 insertions(+), 7 deletions(-) rename src/librustc_error_codes/error_codes/{E0755.md => E0760.md} (94%) diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs index c0b16c22e4d..97f0c16b4cf 100644 --- a/src/librustc_error_codes/error_codes.rs +++ b/src/librustc_error_codes/error_codes.rs @@ -437,7 +437,7 @@ E0751: include_str!("./error_codes/E0751.md"), E0752: include_str!("./error_codes/E0752.md"), E0753: include_str!("./error_codes/E0753.md"), E0754: include_str!("./error_codes/E0754.md"), -E0755: include_str!("./error_codes/E0755.md"), +E0760: include_str!("./error_codes/E0760.md"), ; // E0006, // merged with E0005 // E0008, // cannot bind by-move into a pattern guard diff --git a/src/librustc_error_codes/error_codes/E0755.md b/src/librustc_error_codes/error_codes/E0760.md similarity index 94% rename from src/librustc_error_codes/error_codes/E0755.md rename to src/librustc_error_codes/error_codes/E0760.md index 0c289146176..e1dcfefebcd 100644 --- a/src/librustc_error_codes/error_codes/E0755.md +++ b/src/librustc_error_codes/error_codes/E0760.md @@ -3,7 +3,7 @@ or `Self` that references lifetimes from a parent scope. Erroneous code example: -```compile_fail,E0755,edition2018 +```compile_fail,E0760,edition2018 struct S<'a>(&'a i32); impl<'a> S<'a> { diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 200263728d9..4646e703496 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -1690,7 +1690,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId, let mut err = struct_span_err!( tcx.sess, span, - E0755, + E0760, "`{}` return type cannot contain a projection or `Self` that references lifetimes from \ a parent scope", if is_async { "async fn" } else { "impl Trait" }, diff --git a/src/test/ui/async-await/issue-61949-self-return-type.stderr b/src/test/ui/async-await/issue-61949-self-return-type.stderr index f57e097c125..4eeef871c5b 100644 --- a/src/test/ui/async-await/issue-61949-self-return-type.stderr +++ b/src/test/ui/async-await/issue-61949-self-return-type.stderr @@ -1,4 +1,4 @@ -error[E0755]: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope +error[E0760]: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope --> $DIR/issue-61949-self-return-type.rs:11:40 | LL | pub async fn new(_bar: &'a i32) -> Self { @@ -6,4 +6,4 @@ LL | pub async fn new(_bar: &'a i32) -> Self { error: aborting due to previous error -For more information about this error, try `rustc --explain E0755`. +For more information about this error, try `rustc --explain E0760`. diff --git a/src/test/ui/impl-trait/bound-normalization-fail.stderr b/src/test/ui/impl-trait/bound-normalization-fail.stderr index c78d4c4a8fd..03aba10cc79 100644 --- a/src/test/ui/impl-trait/bound-normalization-fail.stderr +++ b/src/test/ui/impl-trait/bound-normalization-fail.stderr @@ -21,7 +21,7 @@ help: consider constraining the associated type `::Assoc LL | fn foo_fail>() -> impl FooLike { | ^^^^^^^^^^^^ -error[E0755]: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope +error[E0760]: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope --> $DIR/bound-normalization-fail.rs:43:41 | LL | fn foo2_fail<'a, T: Trait<'a>>() -> impl FooLike { @@ -43,5 +43,5 @@ LL | fn foo2_fail<'a, T: Trait<'a, Assoc = ()>>() -> impl FooLike